Spoilers for this episode.
A Soviet experiment to open a gate ends in an explosion, and the officer overseeing the work gives the surviving scientist a year to succeed. In Hawkins the following summer, Mike and Eleven spend most of their time together, irritating Hopper. Starcourt Mall draws customers away from downtown shops, while Steve works at Scoops Ahoy with Robin. A townwide blackout interrupts the children's cinema trip, and Will feels the familiar chill associated with the Mind Flayer.
Dustin returns from science camp with inventions and news of a girlfriend named Suzie. His friends help carry his powerful radio, Cerebro, up a hill, but lose patience when she does not answer. After they leave, Dustin intercepts a message in Russian. Nancy struggles to get past fetching food and enduring insults at the Hawkins Post, where a caller reports diseased rats. At the abandoned steelworks, rats gather and burst into moving organic matter.
Hopper asks Joyce how to talk to Eleven and Mike, then abandons her gentle approach when Mike mocks him. He gets Mike alone and threatens to keep him away from Eleven unless their behaviour changes. Billy arranges a private meeting with Karen Wheeler, who hesitates before leaving her family. Driving toward the rendezvous, Billy crashes near the steelworks. He investigates the damage, only for an unseen creature to drag him into the building's basement.